GEOS 655: Geodesy and Tectonics

Spring 2009

Version 1: 24 Jan 2009

Class website:

Jeff Freymueller

Elvey 413B

474-7286

The Earth’s crust is constantly in motion, with every part of the surface moving due to plate tectonics, and constantly deforming. The Earth is subject to a variety of periodic, steady and transient deformations. Motion and deformation is characteristic of both the solid earth and the cryosphere, and hydrologic and cryospheric mass changes cause observable deformation of the solid earth. Modern space-based geodetic techniques like the Global Positioning System (GPS) provide the ideal tools for studying the kinematics and dynamics of the earth.

The course is intended to teach you how modern geodetic techniques work, with a focus on GPS, and how they are applied to the study of problems in tectonics and other causes of motion and deformation. It begins with a description of how the measurements are made, followed by a mathematical description of coordinates and strains, and then provides an overview of the mathematical models used to relate observed deformation to tectonic, volcanic, and loading source models. Practical examples and applications are interspersed throughout, and the last few weeks of the class will be dominated by such examples. We will conclude with a discussion of related problems in sea level change, altimetry, and gravity change, which are made using different geodetic tools and provide measurements of the dynamic changes in the cryosphere and hydrosphere.

Textbook

There is no suitable textbook for this course; book publishers have not yet caught up with this fairly new field, although there are several books that cover parts of this course in detail. Xerox copies or PDF files of reading material will be provided. When I assign reading assignments, I expect to you read the material before the next class. That will allow me to use the lecture time to summarize key points and answer your questions, rather than trying to give you the details.

Grading

Students will be assigned several homework assignments, with a mix of analytical and numerical exercises. The homework load will not be very heavy, and will be scheduled to minimize time conflicts with the projects. Numerical exercises will be done using MATLAB or a similar programming environment. In addition, there will be midterm and final projects. The midterm project will be in the form of a written report summarizing, analyzing and synthesizing results from two or more published papers on a similar topic. The final project will be in the form of a written research proposal. In both cases, the students will also make a 10-minute presentation of their report or proposal to the class.

Grades will be based on a combination of homework and the two projects:

Homework 40%

Midterm Project 25%

Final Project 35%

Projects

There will be two projects, a midterm project and a final project. Each will involve a short presentation by each student. For the midterm project, each student will select some part of the world, or some specific process, and do a survey of the existing literature. Each student will write a report that will summarize what is happening there, what the interesting questions are, and what results have been obtained to date. For the final project, each student will write a mock research proposal to carry out a specific investigation using geodetic techniques or data. The proposal should include a description of the question to be answered and why that is interesting and important, background information from past relevant studies, and a description of how you will carry out the proposed work. The final project can be on a similar topic to the midterm project, although that is not required.

Each project replaces a few weeks of homework assignments, and I expect you to spend an appropriate amount of time on the projects. These are not things to try to do the night before they are due. Topics for the projects will be chosen by the students with my approval. Any topic relevant to the class is acceptable, although in the interests of fairness all students need to choose projects that are distinct from their personal research work or anything otherwise assigned by their advisor. The rule is simple: your class project can’t be something you were already going to be doing anyway during this semester. But of course it can (and should) be something you find interesting, and it may have a peripheral connection to your own pre-existing research plans.

Class Time and Location

Class will meet Tuesdays and Thursdays from 3:30 to 5:00 pm, plus a few Wednesdays from 3:30 to 5:00 pm. I will be out of town during all or part of two weeks of the semester, so there will be no class at those times. We will meet in the 3rd floor Elvey Record Reading Room (aka AVO meeting room).

Detailed Schedule

Day / Date / Lecture Topic
Tue / Jan 27 / 1. Introduction; What is Geodesy; History of Geodesy applied to tectonics
Thu / Jan 29 / 2. Measurement systems; sampler of applications; online resources
Tue / Feb 3 / 3. Measurement systems: Global Positioning System (GPS)
Thu / Feb 5 / 4. Measurement systems: Global Positioning System (GPS)
Tue / Feb 10 / 5. Measurement systems: Global Positioning System (GPS): time series, practical reference frames
Wed / Feb11 / 6. Measurement systems: Kinematic GPS and GPS “Seismology”
Thu / Feb 12 / 7. Measurement systems: InSAR
Tue / Feb 17 / No Class
Thu / Feb 19 / No Class
Tue / Feb 24 / 8. Plate kinematics, rigid plate motions, reference frames in practice; Helmert transformations; ITRF
Wed / Feb 25 / 9. Practical applications: steady plate boundary deformation
Thu / Feb 26 / 10. Coordinates and transformations; vectors; Displacements and strains; tensors; Displacement gradient tensor
Tue / Mar 3 / 11. Strain tensor; Rotation; Line length and angle measurements; Frank’s method;
Wed / Mar 4 / 12. Strain in the real world; simple shear and pure shear; dilatation; large-scale strain maps
Thu / Mar 5 / Presentation of Midterm Projects
Tue / Mar 10 / SPRING BREAK
Thu / Mar 12 / SPRING BREAK
Tue / Mar 17 / 13. Global Strain Rate Maps
Wed / Mar 18 / 14. Measurement systems: terrestrial measurements, datum defects, special solutions; Singular Value Decomposition, Model coordinate solution
Thu / Mar 19 / 15. Description of faults; Earthquake cycle
Tue / Mar 24 / 16. Dislocation theory; Screw and edge dislocations;
Thu / Mar 26 / No Class
Tue / Mar 31 / 17. Glacial Isostatic Adjustment
Thu / Apr 2 / 18. Loading deformation
Tue / Apr 7 / 19. Practical applications: earthquakes; seismic vs. aseismic slip
Thu / Apr 9 / 20. Practical applications: slow slip and stress transfer
Tue / Apr 14 / 21. Practical applications: postseismic deformation
Thu / Apr 16 / 22. Practical applications: volcanoes I
Tue / Apr 21 / 23. Practical applications: volcanoes II
Thu / Apr 23 / 24. Tides and tide gauges; The sea level problem I
Tue / Apr 28 / 25. Tides and tide gauges; The sea level problem II
Wed / Apr 29 / 26. Altimetry and land/sea level change
Thu / Apr 30 / Presentation of Final Projects